1. Field of the Invention
The present invention relates to a textile structure for producing structural members such as reinforced spars of composite material, and to a method of producing the same. More particularly, the present invention relates to a textile structure which provides high torsional rigidity to reinforced composite materials such as reinforced spars suitable for use as structural parts for spacecraft, aircraft, automobiles, linear motor cars and the like, and to a method of producing the same. The present application is related to U.S. patent application Ser. No. 07/151,049 filed on Feb. 1, 1988, now U.S. Pat. No. 4,788,101, dated Nov. 29, 1988 wholly incorporated by reference herein.
2. Description of Prior Art
Structural parts such as airplane wings are subjected to high tensile and compressive loads. Fiber-reinforced resin composite materials have begun to be used as raw materials for spars required to have such specific strength. In many cases, spars of fiber-reinforced composite material of this kind have an I-, H-, U-, T-, or L-shaped cross section.
As for textile structures for reinforced composite materials having such cross-sections, Japanese Utility Model Application Laid-Open Specification No. 62-79900 and Japanese Patent Application Laid-Open Specification No. 61-53458 disclose laminated structures of textile filament having a three-dimensional construction of a three-axis orientation type in which textile filaments are laminate along X-, Y- and Z-axes which are orthogonal to each other. Further, Japanese Patent Application Laid-Open Specification No. 62-117842 discloses a base material of I-shaped cross-section in the form of a multilayer fabric opened to assume a three-dimensional configuration.
However, a conventional spar using reinforced members such as described above is constructed such that the laminated structure of textile filament has only a three-dimensional laminated construction of the so-called three-axis orientation type in which the directions of layout of textile filament cross each other. Such a conventional spar exhibits satisfactory strength against tensile, compressive and bending loads acting axially of the textile filaments. However, in the case where the spar has an increased length and when the axial direction of the textile filaments does not coincide with the direction of action of the load, such as when a torsional load is applied, the spar exhibits insufficient strength. As a result, the spar will deform. For example, a fracture or the like may develop due to the inability of a spar to bear the torsional load in a spar used as the main wing or tail assembly of an airplane.
An object of the invention is to provide a textile structure and a method of producing the same which are capable of eliminating the lack of torsional rigidity which has been a problem in spars of fiber-reinforced composite material which use as a reinforcing member a laminated structure of textile filament having a three-dimensional construction of the conventional three-axis orientation type.